Lawyers for Samsung accused the US company of patenting obvious designs like rectangular phones, and claimed that much of the technology in the iPhones was invented by Samsung.
The trial in the US District Court in San Jose, California,centres on Apple's 2.5-billion dollar (2-billion euro) claim that Samsung copied its designs for mobile phones and tablet computers.
Samsung has countersued alleging that Apple has violated numerous patents registered to the South Korean electronics giant.
"At its highest corporate level, Samsung decided to simply copy every element of the iPhone," Apple's lawyer Harold J McElhinny said, according to The Wall Street Journal.
"Apple didn't invent the rectangular shape form-factor you keep seeing," responded Samsung lawyer, Charles Verhoeven, arguing that Apple had no right to claim a "monopoly on a rectangular shape."
The two companies, which are close business partners as well as fierce rivals in the mobile technology sector, are locked in patent litigation all over the world.//DPA